C4: ATTITUDE OF BEDS Flashcards
Is the study of factors such as origin, occurrence, classification, type and effects of various secondary structures like folds, faults, joints, rock cleavage and are different from those primary structures such as bedding and vesicular structure, which develop in rocks at the time of their formation.
STRUCTURAL GEOLOGY
Is the theoretical and applied science of the mechanical behavior of rock. It is that branch of mechanics concerned with the response of rock to the force fields of its physical environment
ROCK MECHANICS
It is an important field in civil engineering as it applies in the majority of infrastructure projects including dams, roads, tunnels, bridges, buildings, and protection of slopes.
ROCK MECHANICS
A general term for the orientation of a line or plane.
Attitude
refers to the three-dimensional orientation of planar and linear features such as a bed, joint or a fold.
Attitude
A compass direction of the line measured in degree (0-360) clockwise from north with north=0, east=90, south=180, west=270. Expressed In Three Digits (000).
AZIMUTH
A compass direction measured 0-90 degrees from north or south.
QUADRANT
Also known as top view.
MAP VIEW
It is the bird’s eye point of view of the earth surface.
MAP VIEW
Representation of a geometry on a plane perpendicular to the earth’s surface.
CROSS-SECTIONAL VIEW
PLANAR
- Two important principle components: ______ AND ______
-Geologic structures:______, _____, ______, ____
strike and dip
beddings, joints, faults, axial planes, etc.
3 Methods In Determining The Attitude Of Planar:
- Strike and Dip
- Right Hand Rule
- Dip-Line Trend and Plunge
This system is used to describe the orientation of inclined
bedding which is named after the two important principal components in describing 3D spatial orientation.
STRIKE AND DIP
The azimuth direction line formed by the intersection of horizontal plane and the plane intersect.
STRIKE AND DIP
The maximum slope of a plane, measured from horizontal. The ____
direction is always perpendicular to strike.
dip
Dip values are always in the range of _______. A dip angle of 0 defines horizontal plane with 90 describes a vertically oriented plane
0-90
DIP
The maximum slope of a plane, measured from horizontal. The dip
direction is always perpendicular to strike.
Dip values are always in the range of 0-90. A dip angle of 0 defines horizontal plane with 90 describes a vertically oriented plane
✓ 0-20 – _________
✓ 20-50 – _________
✓ 50-90 – ___________
shallow
moderate
steep
is the inclination of a plane measured in a vertical plane trending perpendicular to the strike.
TRUE DIP
inclination of a plane measured in vertical plane that is not perpendicular to the strike.
APPARENT DIP
Direction of a line of intersection between a tilted plane and a horizontal plane.
STRIKE
Geologist use a _____________ to measure strike and dip
BRUNTON or CLINO COMPASS
This rule is followed by most geologist in the world for consistency. The azimuth direction of the strike is recorded such that true dip is inclined to the right of the observer. In this case, the strike azimuth could be to any quadrant.
2.THE RIGHT HAND RULE
________ is when your are facing the strike direction and your right side is dipping downward.
Right hand rule
As the name suggests, this method is similar to the method trend and plunge of in determining linear attitude. This method relies on the implicit 90 degrees angle between true dip azimuth and the strike.
DIP-LINE TREND AND PLUNGE
In this method, the observer measures the dip azimuth and then the true dip angle. Because strike of a plane always has a trend of 90
degrees form the dip trend, one may simply record the dip trend and the angle of a plane.
DIP-LINE TREND AND PLUNGE
LINEAR
-Two important principle components: ____ AND ____
-Geologic structures: _____, _____, _______, ______, _____
trend and plunge
folds, hinges, elongated minerals, cleavage, bedding intersection, etc.
2 METHODS OF DETERMINING THE ATTITUDE OF LINEAR
- Trend and Plunge
- Pitch/Rake
-Is the projecting line onto the horizontal plane. It is the azimuth
direction of a line in map view (top view).
- TREND AND PLUNGE
Since _____ is measured in top view, vertical line has no definable trend.
trend
________ is the angle of inclination of a line measured in a vertical plane. It is the angle from the horizontal line to the line
itself. It shows how the particular line dips with respect to the horizontal line.
plunge
This method is used when it is difficult to measure the trend due to the steepness of the plunge. Pitch, synonymous to rake, is the angle between the line and the strike of the plain that contains the line
PITCH RAKE
